ci: set up dependabot; bump go version

.github/dependabot.yaml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: gomod
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/go.yml

@@ -12,10 +12,12 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v3
+
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: '1.21'
+        go-version: '1.22'
+
     - name: Build
       run: go build -v ./.
 
@@ -24,9 +26,9 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v4
+
     - name: Install Nix
       uses: DeterminateSystems/nix-installer-action@main
-    - name: Nix Magic Cache
-      uses: DeterminateSystems/magic-nix-cache-action@main
+
     - name: Build with Nix
       run: nix build .# -Lv